Aim 3. A) To determine whether significant anemia preceding a RBC transfusion is associated with impaired intestinal oxygenation, and whether a RBC transfusion temporarily increases splanchnic oxygenation. We postulate that the CSOR will be low (<0.75) at baseline measurement in infants with hemodynamically significant anemia, and that RBC transfusion will temporarily increase intestinal perfusion in that particular group of babies.